I have an Asus ZenWatch. Below should be able to be done on any Android Wear device. In no particular order I use it for the following:
Check New Email
Check Caller ID
Check Calendar and Agenda
Check Google Now Cards (includes traffic card for my route home)
Check Other phone notifications
Check steps walked
Check Heart rate
and Check the Time
Some Android Watches have a speaker in addition to the microphone so you answer and talk through your watch for phone calls. My watch can store music on the watch itself and play back through a paired BT headphones without my phone present. One could play games, but I do not see any point.
I am down to about 40% by Midnight most days. I do not see much issue with recharging it every day as I take it off every night and sticking in the charging cradle just means it is easy to find in the morning.
Android wear becomes really useful over other options if you enable Google Now. The latest generation of Android Wear watches actually look like a watch (Moto360, LG G Watch R, Asus ZenWatch). If those things do not matter, then get a Pebble or one of the high end Fitbits like a Charge or Surge, or a Nevo Watch ( http://igg.me/at/nevo/x/813785... ). The Nevo is a real watch, with basically a Fitbit Flex built in, and add in colored led notification lights. You will not be able to read an SMS or email on your Nevo, but you can tell the difference when your watch vibrates from a new notification.